This project will examine the effect of vaccination against an oncogenic, lymphotropic herpesvirus, Herpesvirus sylvilagus, on (1) increasing the resistance to infection by the virulent virus, (2) regulating the clinical disease, including the induction of malignant lymphoma, and (3) reducing the chronic carrier state established by the virulent virus. This will include the use of attenuated live vaccine given by the oral route and inactive vaccine given in adjuvant.